Day7.java

package com.sbaars.adventofcode.year23.days;

import com.sbaars.adventofcode.common.map.CountMap;
import com.sbaars.adventofcode.year23.Day2023;

import java.util.Comparator;

import static com.sbaars.adventofcode.util.AoCUtils.zipWithIndex;
import static com.sbaars.adventofcode.util.DataMapper.readString;

public class Day7 extends Day2023 {

  public Day7() {
    super(7);
  }

  public static void main(String[] args) {
    new Day7().printParts();
  }

  public record Hand(String cards, int bet) {
  }

  @Override
  public Object part1() {
    return solve(this::compareHands);
  }

  @Override
  public Object part2() {
    return solve(this::compareHands2);
  }

  private long solve(Comparator<Hand> comparator) {
    return zipWithIndex(
        dayStream().map(s -> readString(s, "%s %i", Hand.class)).sorted(comparator)
    ).mapToLong(hand -> (long) hand.e().bet * (hand.i() + 1)).sum();
  }

  public int compareHands(Hand h1, Hand h2) {
    int setRank = Integer.compare(getRank(h1.cards), getRank(h2.cards));
    if (setRank != 0) return setRank;
    for (int i = 0; i < h1.cards.length(); i++) {
      int cardValue = Integer.compare(cardValue(h1.cards.charAt(i)), cardValue(h2.cards.charAt(i)));
      if (cardValue != 0) return cardValue;
    }
    return 0;
  }

  public int getRank(String cards) {
    CountMap<Character> charCounts = getCharacterCounts(cards);
    if (charCounts.containsValue(5)) {
      return 7;
    } else if (charCounts.containsValue(4)) {
      return 6;
    } else if (charCounts.containsValue(3) && charCounts.containsValue(2)) {
      return 5;
    } else if (charCounts.containsValue(3)) {
      return 4;
    } else if (charCounts.values().size() == 3) {
      return 2;
    } else if (charCounts.values().size() == 4) {
      return 1;
    }
    return 0;
  }

  public int getRankJ(String cards) {
    CountMap<Character> charCounts = getCharacterCounts(cards);
    if (charCounts.containsValue(4)) {
      return 7;
    } else if (charCounts.containsValue(3)) {
      return 6;
    } else if (charCounts.values().stream().allMatch(i -> i == 2)) {
      return 5;
    } else if (charCounts.containsValue(2)) {
      return 4;
    }
    return 1;
  }

  public int getRankJJ(String cards) {
    CountMap<Character> charCounts = getCharacterCounts(cards);
    if (charCounts.containsValue(3)) {
      return 7;
    } else if (charCounts.containsValue(2)) {
      return 6;
    }
    return 4;
  }

  public int setRankJJJ(String cards) {
    CountMap<Character> charCounts = getCharacterCounts(cards);
    if (charCounts.containsValue(2)) {
      return 7;
    }
    return 6;
  }

  private static CountMap<Character> getCharacterCounts(String cards) {
    CountMap<Character> charCounts = new CountMap<>();
    for (char c : cards.toCharArray()) {
      charCounts.increment(c);
    }
    return charCounts;
  }

  public int cardValue(char c) {
    return switch (c) {
      case 'A' -> 14;
      case 'K' -> 13;
      case 'Q' -> 12;
      case 'J' -> 11;
      case 'T' -> 10;
      default -> c - '0';
    };
  }

  public int compareHands2(Hand h1, Hand h2) {
    int setRank = Integer.compare(resolveWildcards(h1.cards), resolveWildcards(h2.cards));
    if (setRank != 0) return setRank;
    for (int i = 0; i < h1.cards.length(); i++) {
      int cardValue = Integer.compare(cardValue2(h1.cards.charAt(i)), cardValue2(h2.cards.charAt(i)));
      if (cardValue != 0) return cardValue;
    }
    return 0;
  }

  public int resolveWildcards(String cards) {
    CountMap<Character> charCounts = getCharacterCounts(cards);
    if (!charCounts.containsKey('J')) return getRank(cards);

    cards = cards.replace("J", "");
    return switch (charCounts.get('J')) {
      case 1 -> getRankJ(cards);
      case 2 -> getRankJJ(cards);
      case 3 -> setRankJJJ(cards);
      case 4, 5 -> 7;
      default -> throw new IllegalStateException();
    };

  }

  public int cardValue2(char c) {
    return switch (c) {
      case 'A' -> 14;
      case 'K' -> 13;
      case 'Q' -> 12;
      case 'J' -> 1;
      case 'T' -> 10;
      default -> c - '0';
    };
  }
}